A-LevelChemistryReaction kineticsFeb/Mar 2016Paper 1 Q381 Mark
Chlorine atoms in the upper atmosphere cause the breakdown of ozone. Cl + O₃ → O₂ + ClO ClO + O → Cl + O₂ Which statements are correct when referring to these chlorine atoms? 1 The chlorine atoms act as catalysts. 2 The chlorine atoms are free radicals. 3 The chlorine atoms are formed by heterolytic fission of a covalent bond in chlorofluorocarbons.
A1, 2 and 3 are correct
B1 and 2 only are correct
C2 and 3 only are correct
D1 only is correct
✓ Correct Answer
The correct answer is B: 1 and 2 only are correct
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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